package org.apache.lucene.document;

/**
 * Licensed to the Apache Software Foundation (ASF) under one or more
 * contributor license agreements.  See the NOTICE file distributed with
 * this work for additional information regarding copyright ownership.
 * The ASF licenses this file to You under the Apache License, Version 2.0
 * (the "License"); you may not use this file except in compliance with
 * the License.  You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

import java.util.HashMap;
import java.util.List;
import java.util.Map;

/**
 * A FieldSelector based on a Map of field names to FieldSelectorResults
 * 
 * @author Chuck Williams
 */
public class MapFieldSelector implements FieldSelector {

	Map fieldSelections;

	/**
	 * Create a a MapFieldSelector
	 * 
	 * @param fieldSelections
	 *            maps from field names (String) to FieldSelectorResults
	 */
	public MapFieldSelector(Map fieldSelections) {
		this.fieldSelections = fieldSelections;
	}

	/**
	 * Create a a MapFieldSelector
	 * 
	 * @param fields
	 *            fields to LOAD. List of Strings. All other fields are NO_LOAD.
	 */
	public MapFieldSelector(List fields) {
		fieldSelections = new HashMap(fields.size() * 5 / 3);
		for (int i = 0; i < fields.size(); i++)
			fieldSelections.put(fields.get(i), FieldSelectorResult.LOAD);
	}

	/**
	 * Create a a MapFieldSelector
	 * 
	 * @param fields
	 *            fields to LOAD. All other fields are NO_LOAD.
	 */
	public MapFieldSelector(String[] fields) {
		fieldSelections = new HashMap(fields.length * 5 / 3);
		for (int i = 0; i < fields.length; i++)
			fieldSelections.put(fields[i], FieldSelectorResult.LOAD);
	}

	/**
	 * Load field according to its associated value in fieldSelections
	 * 
	 * @param field
	 *            a field name
	 * @return the fieldSelections value that field maps to or NO_LOAD if none.
	 */
	public FieldSelectorResult accept(String field) {
		FieldSelectorResult selection = (FieldSelectorResult) fieldSelections
				.get(field);
		return selection != null ? selection : FieldSelectorResult.NO_LOAD;
	}

}
